Oxidative stress in COPD patients, smokers, and non-smokers.

BACKGROUND Oxidative stress has been known for having a key role in pathogenesis of many diseases. The aim of this study was to investigate the oxidative stress and also the relationship between antioxidant system statuses and lung function in patients with COPD and smokers and non-smokers subjects. METHODS Thirty subjects with COPD, 30 smokers, and 30 healthy non-smokers participated in this study. The investigation included determination of the lung function and the measurements of plasma ceruloplasmin, ferritin, and total antioxidant capacity, and also erythrocyte glutathione peroxidase, glutathione reductase, superoxide dismutase, and catalase. RESULTS Plasma ceruloplasmin, ferritin, erythrocyte glutathione peroxidase, and glutathione reductase were not significantly different between the studied groups. Subjects with COPD and smokers had lower catalase and superoxide dismutase activity (P < .001) than the non-smoker group. Levels of antioxidant capacity were significantly lower in subjects with COPD and smokers than in the non-smoker group (P < .001). Regression analysis revealed no correlations between antioxidant status and spirometric data. CONCLUSIONS Decreased total antioxidant capacity in plasma of subjects with COPD and smokers suggests an increased oxidative stress in this group. However, no relationship was found between lung function and antioxidant systems status in COPD subjects.